Machine and method for the continuous treatment of a fabric

ABSTRACT

The machine comprises in combination: means ( 7 ) for supplying the fabric (T); means ( 9 ) for extracting the fabric; at least one first tank ( 1 ) and one second tank ( 3 ) which are positioned in series and between which a pneumatic transfer member ( 5 ) for transferring the fabric alternately from the first tank to the second tank and vice versa is arranged. The pneumatic transfer member is pivotable so as to assume at least two positions depending on the direction of feeding of the fabric through said pivoting transfer member.

TECHNICAL FIELD

The present invention relates to a machine for the continuous treatmentof a fabric. More particularly, the invention relates to a machine forthe continuous treatment of a fabric both in open width form andpreferably in rope form, with or without immersion in a bath.

The invention also relates to a method for the continuous treatment of afabric.

STATE OF THE ART

In the field of the processing and finishing of fabrics, machines whichperform the treatment of lengths of fabric both with and withoutimmersion in a bath are known, said machines conveying the fabric alonga path where the fabric itself undergoes the mechanical action of one ormore mechanical members and, if necessary, a chemical action by means ofenzymes and/or a thermal action.

This type of machine normally operates in a discontinuous cycle. Thismeans that a section of fabric of finite length is introduced into themachine and closed, joining together the leading end and tail end of thesection and forming a kind of ring. This ring of fabric is made tocirculate a sufficient number of times, i.e. for a sufficient treatmentperiod, along the treatment path. Once treatment has finished, themachine is stopped, if necessary depressurized, opened and the treatedfabric is extracted from it and replaced with a new fabric to betreated.

This type of machine has the drawback that the machine must befrequently stopped for loading and unloading. This results in lostproduction time and high labor costs. The need to depressurize and coolthe machine (when it is working under pressure and/or at temperature)also results in a notable expenditure of energy.

Machines which perform this type of processing operation in a continuouscycle have therefore been developed. In these machines the fabric isintroduced at one end of the machine, passes through the machine along atreatment path and is extracted gradually from the machine at theopposite end of the path. Inside the machine a supply of fabric isformed, this supply moving at a faster speed than the speed of insertionand extraction of the fabric into/from the machine, such that eachsection of fabric undergoes more than one treatment along the pathinside the machine.

GB-A-2,158,472 describes a machine of this type, for the continuoustreatment of a fabric in open width form. In this machine, the fabric isgradually introduced inside a first chamber and gradually extracted froma second chamber. The two chambers are joined together by a pneumaticpath which has the form of an overturned “U” and along which the openfabric is conveyed first in one direction and then in another directionby means of air jets. The mechanical processing operations which may beperformed on the fabric with this machine are somewhat limited ineffect. Moreover, conveying of the fabric is difficult owing to thewinding nature of the path and the limited efficiency of the air jetswhich act on the fabric during treatment.

EP-A-0,341,183 describes another machine for the treatment of a fabricagain in open width form and continuously. In this case, inside themachine, the fabric is transferred alternately from one section toanother using a pneumatic system and is made to strike againstmechanical treatment members arranged facing the outlets of a pneumaticconveying duct. In this case also, the efficiency of the treatment islimited.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the invention is to provide a machine for the continuoustreatment of a fabric, of the type comprising at least two tanksarranged in series and a pneumatic transfer member for transferringalternately the fabric between the tanks, which machine has a greaterefficiency than the machines known hitherto.

These and further objects and advantages, which will become clear topersons skilled in the art from reading of the text which follows, areobtained essentially with a machine of the abovementioned type in which:

-   -   the pneumatic transfer member is pivotable so as to assume at        least two positions depending on the direction of feeding of the        fabric through said pivoting transfer member;    -   in front of the transfer member, opposite the first and second        tanks, two respective grille structures are arranged, the fabric        being made to strike against said structures as a result of the        kinetic energy imparted to it by the transfer member;    -   and in which, on the opposite side of each grille structure,        with respect to the transfer member, a respective suction mouth        is arranged, said mouth sucking in the conveying air emerging        from the transfer member.

The pivoting movement of the transfer member, which may in practice be adouble Venturi tube, facilitates extraction of the fabric from thepick-up tank and its expulsion on the opposite side. The suction of airperformed on the opposite side of each grille to the side from where thefabric is “fired out” by the transfer member, increases the air flowwhich conveys the fabric and causes it to strike the grille. Thisincreases the treatment efficiency of the machine. A greater treatmentefficiency also allows a reduction in the number of passes which eachsection of fabric must undergo inside the machine, with a consequentincrease in the productivity of the machine itself. As a result of thesucked-in air flow, it is possible to achieve a high acceleration of thefabric upon every reversal in the direction of feeding and thereforeachieve the necessary speed for obtaining effective treatment even whenthe supply of fabric present inside the machine is relatively small.

“Grille structure” is understood as meaning any structure suitable forforming an impact surface for the fabric and at the same time able toallow the air to pass through. It may be formed by a series ofhorizontal and/or vertical bars, a perforated metal sheet, a continuousmetal sheet with a central slit or a series of slits varyingly arranged,or other system.

Further advantageous features of the machine according to the inventionare defined in the accompanying dependent claims.

It must be noted that the machine may be designed for treatment of thefabric in open width form. In this case the transfer member will be inthe form of a duct with a narrow and elongated cross-section. Similarlythe grilles against which the fabric strikes will be sufficiently wideto receive the entire width of the fabric.

Preferably, however, the machine is designed for the treatment of fabricin rope form. In this case the transfer member will be in the form of aconveying duct with a smaller cross-section, and in particular with asmaller difference between the length and the width of thecross-section. Preferably, the duct will have a rectangular shape.

The treatment of fabric in rope form produces results which are betterin terms of effectiveness of the treatment, since greater mechanicalprocessing of the fibers is achieved, with a consequent breakage of thesaid fibers and softening of the fabric.

The machine may be used for processing operations involving drying,steaming and treatment, in specific and other kinds of baths, ofcontinuous lengths of fabric.

The machine may also perform the treatment of a dry or moist fabric. Ina particular embodiment, it is also possible to envisage that the tankshave inside them a bath, for example containing suitable enzymes orother chemical products intended to have on the fabric an effectcombined with the mechanical action which the fabric undergoes duringtransfer inside the transfer member and striking against the grilles.

The object of the invention is also to provide a method for thecontinuous treatment of a fabric, which is particularly efficient.

Substantially according to the invention, the method for treatment ofthe fabric comprises the steps of:

-   -   gradually introducing the fabric into a first tank of a        treatment machine;    -   gradually extracting the fabric from a second tank, forming a        supply of fabric which is transferred pneumatically from the        first tank to the second tank and vice versa, undergoing a        mechanical treatment;    -   pneumatically propelling the fabric alternately against a first        or against a second grille structure associated with the first        and the second tank respectively, generating an output air        current acting against a first side of the respective grille        structure and an intake air current on the opposite side of said        grille.

It must be understood that the machine may also have more than two tankswhich are arranged in series and which may be aligned or also situatedalongside each other, with a suitable system for deviating the path ofthe fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to thedescription and the accompanying drawing which illustrates a practicalembodiment of the invention. More particularly, in the drawing:

FIG. 1 shows a perspective view of the internal part of the machine as awhole, from which the walls and the external housing have been removedin order to show the internal components;

FIG. 2 shows a perspective and partially sectioned view of a detail ofthe double Venturi tube;

FIG. 3 shows a detail of one of the ends of the suction ducts in whichthe suction mouths are formed.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

FIG. 1 shows the internal components of the machine in a perspectiveview, all the external containing walls and housing having been removedso as to provide an overall view of the inside of the machine itself.

In the example illustrated, the machine is designed for the treatment offabric in rope form, as mentioned above, but may also be designed forthe treatment of fabric in open width form.

The machine has inside it a first tank 1 and a second tank 3 which arepositioned in series along a path for treatment of the fabric T andbetween which a transfer member denoted overall by 5 is arranged. Thetank 1 has, associated with it, a conveying unit 7 for introduction ofthe fabric T, while the tank 3 has, associated with it, a secondconveying unit 9 for extraction of the treated fabric from the machine.The two conveying units 7 and 9 have a plurality of cylinders, at leastone of which is motorized so as to impart to the fabric T the necessaryspeed for insertion and extraction from the machine in such a way as toobtain a continuous gradual insertion and continuous gradual extractionof the fabric into and from the machine in the direction indicated bythe arrows.

Inside the machine, the fabric T forms a supply which is distributedbetween the tanks 1 and 3. In the condition shown in FIG. 1, the supplyof fabric T is situated practically all inside the tank 3 and thetransfer member 5 is positioned so as to remove the supply of fabricfrom the tank 3 and transfer it into the tank 1 in the manner which willbe described below. The speed of transfer of the supply from one tank toanother is preferably much greater than the speed of insertion andextraction of the fabric into/from the machine, such that each sectionof fabric undergoes inside the machine, before emerging from it, aplurality of treatment passes, being transferred several times from onetank to the other.

Slides 11 and 13 on which the fabric T rests are respectively arrangedinside the tanks 1 and 3. The slides 11 and 13 are shaped, in theirbottom part, so as to form a sort of cradle and extend upward and towardthe transfer member 5, forming guide surfaces for the fabric T. Theslides 11 and 13 are made of or lined with a material having a lowcoefficient of friction, for example Teflon®, in order to facilitatesliding of the fabric.

The transfer member 5 pivots about an axis A-A which is horizontal andperpendicular to the direction of feeding of the fabric through themachine. The transfer member 5 is symmetrical with respect to the axisA-A and has two opposite mouths 5A and 5B (see in particular FIG. 2also).

Two grille structures 15 and 17 are provided in positions facing eachother, opposite the transfer member 5, so as to be located respectivelyopposite the mouth 5A and the mouth 5B. As can be seen in FIG. 1, whenthe transfer member 5 is located in the position shown there, the mouth5A is located exactly facing the grille structure 15, while the mouth 5Bis located directed downward and pointing toward the slide 13, i.e. thebottom of the tank 3. By pivoting the transfer member 5 so as to bringit into a position which is symmetrical with respect to that shown inFIG. 1, relative to the horizontal plane containing the axis A-A, themouth 5A will be located pointing downward, i.e. toward the bottom ofthe tank 1, while the mouth 5B will be located facing the grillestructure 17.

Respective suction mouths 19 and 21, which are formed at the ends of aU-shaped duct denoted by 23 and lying in a substantially horizontalplane are located behind the grille structures 15 and 17. Respectiveopening and closing gates indicated by 25 and 27 are located inside theduct 23, in the vicinity of the suction openings 19 and 21 (see inparticular also the detail in FIG. 3).

In the condition shown in FIG. 1, the gate 25 associated with thesuction mouth 19 is located in an open position, while the gate 27associated with the suction mouth 21 is located in the closed position.

The suction duct 23 is connected to the intake of a fan 29, the output31 of which is connected, via a gate 33, to the pneumatic transfermember 5. By means of the gate 33, the air flow from the output 31 maybe deviated into one or other of the two ducts 35A and 35B which areconnected by means of respective headers 37A, 37B (FIG. 2) to thetransfer member 5.

As can be seen in particular in FIG. 2, the transfer member 5 has anexternal casing defining the mouths 5A and 5B inside which a rectangularthrough-duct 39 is located. A space divided by means of inclined walls43 into two parts is defined between the external casing, indicated by41 in FIG. 2, and the internal through-duct 39. One part of this spaceis connected to the mouth 5A and to the duct 35A, while the other partis connected to the mouth 5B and to the duct 35B.

With this arrangement depending on the position of the gate 33, air isintroduced at high speed into one or other of the two parts into whichthe space or cavity defined between the casing 41 and the rectangularduct 39 is divided, and therefore an air flow emerging from the mouth 5Aor 5B, respectively, is produced. The air flow draws along the fabricintroduced into the rectangular duct 39.

The pivoting of the transfer member 5 about the axis A-A is controlledby means of an actuator 43, for example a cylinder/piston actuator (FIG.1).

The machine described hitherto functions as follows.

The fabric T is gradually introduced into the first tank 1 by means ofan inward conveying unit 7 and gradually extracted from the tank 3 bymeans of an outward conveying unit 9. The supply of fabric which isformed in the two tanks is transferred alternately from one tank to theother by means of the transfer member 5. In the condition shown in FIG.1, the supply of fabric present in the tank 3 is gradually extractedfrom it and transferred in the tank 1. This operation is performed bythe transfer member 5 which, during this step, is inclined with respectto the horizontal so that its mouth 5A is directed upward against thegrille structure 15, while the mouth 5B is directed downward andpointing toward the slide 13 and the bottom of the tank 3. The mouth 5Btherefore forms an inlet opening for the fabric, while the mouth 5Aforms the outlet opening for the fabric and is located substantiallyaligned with the suction mouth 19.

This position facilitates picking up of the fabric from the tank 3 andits propulsion against the grille structure 15 as a result of the airflow generated in the cavity between the casing 41 and the rectangularduct 39 inside the transfer member 5. The gate 33 is located in aposition such as to introduce all the air supplied from the fan 29 intothe duct 35A. The gate 25 inside the suction duct 23 is open, while thegate 27 is closed. This has the effect that an air flow is sucked inthrough the suction mouth 19 and is added to the air flow emitted by thetransfer member 5, thereby increasing the force with which the fabric ismade to strike against the grille structure 15. Basically, the airemerging from the transfer member 5 or at least a part thereof is suckedin by the rear-lying suction mouth 19.

The air sucked in through the suction mouth 19 and the duct 23 is drawnoff by the fan 29 and introduced again into the transfer member 5.

Thus, on the one hand a greater efficiency in the mechanical treatmentof the fabric and on the other hand a greater thermal efficiency isobtained since the air used for the pneumatic transfer follows a closedpath inside the machine. If the air has been conditioned, for exampleheated and/or humidified, this avoids dissipation of the energy used forconditioning purposes.

When the fabric supply inside the tank 3 has been used up, the positionof the conveying member 5 is switched by means of pivoting in ananti-clockwise direction and the position of the gates 25, 27 and 33 isalso switched. The output air flow from the fan 29 is then introducedthrough the duct 35B into the part of the cavity between the casing 41and the tube 39 which communicates with the mouth 5B. The fabric is inthis way removed by means of the transfer member 5 from the slide 11 andthen from the tank 1 and propelled against the grille structure 17.

The machine may be suitably completed with a burner 51, for example ofthe gas type, for generating the heat necessary for keeping the aircirculating inside the machine heated. The air is heated by means of aheat exchanger as it passes from the suction duct 23 to the fan 2.

Extractable filters 53 for removing any loose pile released by thefabric are also provided inside the suction duct 23.

Deflectors 55, 57 for directing and containing the air flow are alsoprovided above the ends of the suction duct 23 opposite the grillestructures 15 and 17.

The machine may be suitably equipped with ducts for releasing the usedair and introducing fresh air so as to perform gradual and controlledrenewal of the internal air and therefore control the moisture andtemperature conditions in an efficient manner.

In the example shown, the machine is equipped with two pairs of shapedbrackets which are arranged in front of the mouths 5A and 5B of thetransfer member 5, along the respective slides 11, 13. One of said pairsof brackets can be seen in particular in FIG. 2 and is denoted by 51.These brackets define a passage with a narrow cross-section for thefabric, such that on the entry side of the transfer member 5, the fabricis forced to pass between the brackets before entering into the transfermember 5 itself. On the exit side of the transfer member, the fabricpasses over the brackets 51 which, on this side, do not have any effect.It may also be envisaged to splay the brackets on the fabric exit sideso as to prevent them from hindering the passing movement of the fabricitself. The mutual distance of the brackets may be modified depending onthe width and the thickness of the fabric and/or depending on the degreeof mechanical treatment which they must perform on the fabric.

The effect of the shaped brackets 51 is similar to that of the fabricconstriction ring provided along the closed treatment path in machineswhich operate in a discontinuous cycle: the fabric removed from the tankin which the supply is present undergoes lateral compression by thebrackets 51, while it is pulled by the transfer member 5. The lateralcompression has the mechanical effect of breaking the fibers, inaddition to the effect due to propulsion against the grille structures15, 17.

It is understood that the drawing shows only an example provided by wayof practical demonstration of the invention, it being possible to varythe forms and arrangements of the invention without thereby departingfrom the scope of the idea underlying the invention itself. The presenceof any reference numbers in the accompanying, claims is intended tofacilitate reading of the claims with reference to the description andthe drawing and does not limit the scope of protection defined by theclaims.

1. A machine for the continuous treatment of a fabric, comprising: meansfor supplying the fabric; means for extracting the fabric; between thesupplying means and the extraction means, a section for treatment of thefabric with at least one first tank and one second tank which arepositioned in series and between which a pneumatic transfer member fortransferring the fabric alternately from the first tank to the secondtank and vice versa is arranged; characterized in that: said pneumatictransfer member is pivotable so as to assume at least two positionsdepending on the direction of feeding of the fabric through saidpivoting transfer member; in front of said transfer member, opposite thefirst and second tanks, two grille structures are arranged, the fabricbeing made to strike against them by said transfer member; on theopposite side of each grille structure, with respect to the transfermember, a respective suction mouth is arranged, said mouth sucking inthe conveying air emerging from said transfer member.
 2. Machineaccording to claim 1, characterized in that the two suction mouths areconnected to a single intake duct and are equipped with interceptingmembers for intercepting the flow sucked in alternately through one orthe other of said suction mouths.
 3. Machine according to claim 1,characterized in that it is configured to treat the fabric in rope form.4. Machine according to claim 1, characterized in that said transfermember comprises a pivoting double Venturi tube.
 5. Machine according toclaim 1, characterized in that each of said tanks has, arranged insideit, a respective slide for the fabric, above which the respective grillestructure is situated, said transfer member being able to be oriented soas to have a fabric entry end directed toward the respective slide ofthe tank from which the fabric is removed and an exit end directedtoward the grille structure of the tank into which the fabric istransferred.
 6. Machine according to claim 5, characterized in that saidexit end is substantially aligned with the corresponding suction mouth.7. Machine according to claim 1, characterized in that a deflector fordeviating the air supplied from said transfer member toward therespective suction mouth is arranged above and behind each of saidgrille structures.
 8. Machine according to claim 1, characterized inthat it comprises, in front of the mouths of said transfer member,respective pairs of brackets between which the fabric is passed beforeentering into the transfer member, the mutual distance between thebrackets of each pair being such as to cause lateral compression of thefabric.
 9. Machine according to claim 8, characterized int hat thedistance of the brackets of each pair is adjustable.
 10. Machineaccording to claim 8, characterized in that said brackets may be movedtoward or away from each other depending on the operating conditions ofthe machine.
 11. Method for the continuous treatment of a fabric,comprising the steps of: gradually introducing the fabric into a firsttank; gradually extracting the fabric from a second tank, forming asupply of fabric which is transferred pneumatically from said first tankto said second tank and vice versa, undergoing a mechanical treatment;pneumatically propelling the fabric alternately against a first oragainst a second grille structure associated with said first and saidsecond tank, generating an output air current acting against a firstgrille structure side and an intake air current on the second side ofsaid grille.
 12. Machine according to claim 2, characterized in that itis configured to treat the fabric in rope form.
 13. Machine according toclaim 9, characterized in that said brackets may be moved toward or awayfrom each other depending on the operating conditions of the machine.